1. Field of the Invention
The present invention relates to dust collectors, which are a type of vacuum cleaner and, more particularly, relates to means for eliminating accumulated electrostatic charges which are developed during suctioning of dust and dirt.
2. Description of the Prior Art
As dirt and dust filled air moves through a dust collector or vacuum cleaner, electrostatic charges tend to build up on non-electric components of the dust collector, particularly the suction inlet hose and the dirt collection tank. Such accumulated charges, if not relieved, could produce electric shock to users of the dust collector or damage sensitive electrical equipment in the vicinity of the dust collector. Additionally, where the dust collector is used in an environment subject to an explosive gas mixture, the buildup of electrostatic charges could result in an explosion.
Various techniques have been used in the prior art to prevent or relieve electrostatic charge build-up on parts of a dust collector. For example, the charge may be directed to another part of the dust collector where the charge is dissipated by discharge to the surrounding air. Unfortunately, such discharge may still adversely affect sensitive electrical equipment or, if used in an explosive atmosphere, may still cause an explosion. Additionally, although such techniques tend to discharge the built up electrostatic charge in areas of minimal danger to the user, such danger is not entirely eliminated.
Other prior art suggests applying an electric conductor to the surface of a vacuum cleaner component on which electrostatic charge develops for draining that charge from the surface to a ground potential. For example, a wire in the intake hose conducts charge to ground in U.S. Pat. Nos. 4,715,085; 4,866,565; 2,047,216; and 4,697,300. But, these references do not suggest a convenient way to drain the charge to ground in a tank type dust collector and especially where the drain to ground is in a separable lid over a tank, while the tank and the inlet hose to the tank develop the charge to be drained.